1. Field of the Invention
The present invention relates to a sharpening sheath for a knife or the like.
The invention is also concerned with the combination of a sheath of this type with a knife.
2. Description of the Prior Art
A known blade-sharpening sheath disclosed in French patent No. FR-A-2 223 139 comprises a body in which is defined a passageway for receiving a cutting-blade, an access opening at one end of said passageway, and a sharpening device attached to the body in the vicinity of the access opening. The sharpening device comprises two blade-sharpening elements disposed in a relatively crossed arrangement in order to define a blade-sharpening cavity between said elements. Resilient means have the function of supporting the blade-sharpening elements in such a manner as to permit an increase both in width and depth of the blade-sharpening cavity as well as restoring the blade-sharpening elements to a rest position in which the sharpening cavity has a minimum width and a minimum depth.
When the knife is stored within the sheath or when the knife is withdrawn from the sheath, the cutting edge of the knife-blade slides against the bottom portion of the blade-sharpening cavity which is located at the point of intersection of the blade-sharpening profiles when looking at these latter in the direction of movements of introduction and withdrawal. During these movements, the blade-sharpening elements undergo a relative displacement, thus producing a variation in depth of the blade-sharpening cavity and a correlative displacement of the point of intersection of the profiles along each profile. Thus the profiles develop uniform wear and have a considerably longer service life.
When the appliance is new, the depth of the blade-sharpening cavity in the state of rest permits entry of the blade tip therein when this latter is introduced through the access opening. Should this not be the case, the blade tip would come into abutting contact with the blade-sharpening elements and it would prove impossible to engage the blade within the sheath. However, the result achieved by progressive wear of the profiles is that, in the state of rest, the blade-sharpening cavity increases in depth throughout the lifetime of the appliance. Thus an appliance in which the blade-sharpening elements are worn no longer sharpens the tip region of the knife blade.